Thread arrangement for closure plugs

ABSTRACT

The invention relates to a thread arrangement for screw-on plugs for thermos flasks and other liquid containers, comprising a plug being in thread engagement with a sleeve connected to the neck of the flask or container. The threads of the plug have two leads, and are within a section cut-away around approximately half the circumference. At the beginning of said cut-away portion the end of one thread is connected by means of an intermediate portion with the beginning of the other, overlying thread. The threads of the sleeve comprise two thread portions extending around approximately half the circumference, and being in nonoverlapping relationship to form a generally axial groove enabling the plug to be unscrewed to a stop position in which liquid can be poured from the flask, but from which position the plug must be axially displaced before being unscrewed clear of the flask or container.

United States Patent [19 1 Wetterek THREAD ARRANGEMENT'FOR CLOSURE PLUGS [75] Inventor: StigJohan Emanuel Wetterek,

[52] US. Cl. 222/552, 215/50 [51] Int. Cl B67d 3/00 [58] Field of Search 222/519, 531, 522,

[56] References Cited UNITED STATES PATENTS 3,141,586 7/1964 Wetterek 215/49 3,675,804 7/1972 Micalief 3,679,084 7/1972 Aronson 215/9 [11] 3,785,539 T Jan. 15, 1974 Primary Examiner-Stanley H. Tollberg Assistant ExaminerJames M. Slattery Attorney-Young & Thompson [57] ABSTRACT The invention relates to a thread arrangement for screw-0n plugs for thermos flasks and other liquid containers, comprising a plug being in thread engagement with a sleeve connected to the neck of the flask or container. The threads of the plug have two leads, and are within a section cut-away around approximately half the circumference. At the beginning of said cut'away portion the end of one thread is connected by means of an intermediate portion with the beginning of the other, overlying thread. The threads of the sleeve comprise two thread portions extending around approximately half the circumference, and being in non-overlapping relationship to form a generally axial groove enabling the plug to be unscrewed to a stop position in which liquid can be poured from the flask, but from which position the plug must be axially displaced before being unscrewed clear of the flask or container. i

2 Claims, 3 Drawing Figures THREAD ARRANGEMENT FOR CLOSURE PLUGS The present invention relates to a thread arrangement for screw-on closure plugs for liquid containers, such as thermos flasks for example, comprising a plug now being used, although such plugs are liable to taint the content of the container, Another form of plug is one provided with a conical, plastic sleeve, against which an edge portion of a plastic plug screwed into the threaded sleeve is arranged to seal, The plastic plug in this instance is hollow and is provided with radially extending channels, so that the plug need not be removed from the container in order for the contents to be poured therefrom, but need only be slightly unscrewed. The disadvantage with this type of closure plug, however, is that if the plastic plug is unscrewed-too far, the plug is liable to be freed and when the container is tilted, to fall into the vessel into which the liquid is being poured.

The present invention relates to a system of threads in plugs of the last mentioned type and has for its object to avoid the aforementioned disadvantage encountered with such plugs; this being achieved by the fact that the plug is normally placed in a suitable position to leave sufficient space forthe container to be emptied and cannot be unscrewed from this position unless manipulated in a specific manner.

The invention is mainly characterized in that the plug threads have two leads, that asection of the threads is cut away diametrically around approximately half the circumference and that the end of one thread at the beginning of the cutaway portion is connected by an intermediate portion with the beginning of the other thread, located above said one thread. Further, the threads disposed on the sleeve comprise two thread portions which extend to approximately half-way around the periphery of the sleeve and which, without overlapping, form a generally vertical groove, thereby enabling the plug to be unscrewed to a stop position, at

which position free passage for the liquid from the container to the receiving. vessel is obtained but at which the plug must first be displaced axially before it can be unscrewed free from the container.

The invention will now be described in greater detail with reference to an embodiment thereof illustrated in the accompanying drawing, of which FIG. 1 illustrates the arrangement of the present invention in side view, and shows the plug screwed into the partially sectioned neck portion of a container, closing the same,

FIG. 2 is a side view similar to that of FIG. 1, but showing the plug in a pouring position, and

FIG. 3 is a longitudinal section through the plug and the neck portion and illustrates the path taken by the liquid when pouring from the container.

A plug 1, suitably made from a tasteless thermoplastic, is provided with a gripping surface 2 and a conical sealing surface 3 intended to co-operate with an edge 4 on a sleeve 5 inserted into the neck of a not shown container, sueh as a thermos flask. Located centrally on the bottom surface of the plug 1 is a peg 6 which is non-rotatably mounted in the plug bottom of a cupshaped externally threaded cylinder 7 in a manner such ,as to form between the underneath 'of the plug 1 and the bottom portion of the cylinder 7 a slot 8 which communicates with the interior of the container through holes 9 disposed in the bottom of the cylinder.

The threads 10, 11 on the cylinder 7 have two leads and are cut away diametrically opposite one another through one half turn at a position located approximately centrally of the side of the cylinder, wherewith the end of the thread 10 at the beginning of the cut away portion is directly connected with the end of the overlying thread 11 by a vertically extending portion 12, and, similarly, the thread 11 is connected with the overlying end of the thread 10. Arranged on the cylindrical inner surface of the sleeve 5, so as to extend approximately half way .around the circumference thereof, are two thread portions l3, 14, these thread portions being disposed in non-overlapping relationship to form a groove 15 for the vertically extending portion 12. When the cylinder 7 is turned in the sleeve 5, the thread portions 13 and 14 guide the threads 10 and Ill.

The arrangement operates as follows:

When the container is held upright and the plug 1 is initially screwed into the sleeve 5, the threads 10, ll first engage the thread portions 13 14 in a normal manner, until the plug is screwed into the cut-away portions of the threads 10, 11. The distance. plug will then fall under its own weight, through a distance corresponding to half the pitch of the screw, whereafter the plug is screwed up until the conical sealing surface 3 bears against the edge 4 on the sleeve 5, thereby providing a linear seal.

When opening the plug, the plug is turned through approximately one half turn, whereupon the intermediate portion 12 (FIG. 2) engages the end of thread portion 13, thereby impeding continued opening of the plug. At this position, the sealing surface 3 of the plug has been raised sufficiently from the edge 4 to permit liquid to flow through the holes 9 and the slot 8, when tilting the container. The location of threads 10 and 11 below the removed thread portions obviate all risk of the plug 1 falling out of the container.

In order to remove the plug completely from the container, it is necessary to lift the plug and turn it so that the thread portions 13 and 14 engage the threads nearest the open end of the cylinder 7.

By changing the position of the cylinder 7 in relation to the peg 6, the width of the slot 8 can be adjusted to permit the liquid to be poured from the container at the desired rate of flow. The sleeve 5 is suitably provided with a collar 16 having a thin edge around the opening and into which the liquid runs when being poured. To prevent dripping, the plug 1 may be provided around the periphery of the outer portion of the conical surface 3 with a radially extending, thin flange 17 which readily allows liquid to pass.

What is claimed is:

1. A cap for liquid containers, comprising a sealing cap fixed to a plug having external threads engaging with internal threads of a sleeve connected to the neck of the container, the external threads .of the plug having two leads and being cutaway around approximately half the circumference of the plug about midway of the length of the plug, the cut-away portions of the threads being situated diametrically opposite to each other, the end of one thread at the beginning of the cut-away portion being connected with the beginning of the other overlying thread by means of an intermediate portion,

quiring an axial force at most equal to the weight of the cap and the plug.

2. A cap according to claim 1, in which the plug has the shape of an inverted cylindrical cup having throughholes disposed therein, and a slot between the bottom of the cylinder and the underneath of a gripping portion of the cap, liquid passingthrough said slot only when the cap has been moved to said intermediate position and the container is inclined for pouring. 

1. A cap for liquid containers, comprising a sealing cap fixed to a plug having external threads engaging with internal threads of a sleeve connected to the neck of the container, the external threads of the plug having two leads and being cutaway around approximately half the circumference of the plug about midway of the length of the pluG, the cut-away portions of the threads being situated diametrically opposite to each other, the end of one thread at the beginning of the cut-away portion being connected with the beginning of the other overlying thread by means of an intermediate portion, the internal threads of the sleeve comprising two thread portions which extend around approximately half the circumference and which are arranged in non-overlapping relationship to form a generally vertically extending groove, thereby enabling the cap to be unscrewed to an intermediate position lying between a closed position and an end position in which the cap can be removed from the container, in which intermediate position liquid can be poured from the container but from which the cap can be further unscrewed to said end position after a slight axial displacement requiring an axial force at most equal to the weight of the cap and the plug.
 2. A cap according to claim 1, in which the plug has the shape of an inverted cylindrical cup having throughholes disposed therein, and a slot between the bottom of the cylinder and the underneath of a gripping portion of the cap, liquid passing through said slot only when the cap has been moved to said intermediate position and the container is inclined for pouring. 